Comparison microscope



May 5, 1936. o. uRslNus "2,040,066

COMPARISON MICRCSCOPE Filed April 5, -1955 .'5 Sheets-Sheet 1' wa r May 5, 1936. o. uRslNUs 2,040,066

- COMPARISON MIcRoscoPE Filed April 5, 1935 5 Sheets-Sheet 2 Pe/oe 4er Pff/0e Mer lil IUI

May 5, 1936- o. URslNUs l 2,040,066

COMPARISONMICRCSCOPE Filed April 5, 1935 Patented May 1936 UNITED STA-'rss COMPARISON monosoora l otto Uranus, nathentw, Germany, assigntr to' 1 irm Emil Busch, Aktiengesellschaft, Optische 1 lndustrie; Rathenow, Germany Application April 5, 1935, Serial No. 14,882

In Germany July 9, 1934 7 Claims. (Cl. 88-39) I My inventionv relates to .improvements in microscopes of the twin type. known in the optical trade in Germany as Comparison-Microscopes, and being designed for testing surfaces viz. so as to enable the operator to Yascertain external features of an object to be testedfor instance the face, the absence of scratches etc.-by comparing the surface concerned with the typical or normal surface of a standard articles' In order torender more easily comprehensible the various objects of. this invention and to more fully acquaint the reader with the salient features by which said objects are attained, a brief .synopsis of. the structural and functional properties of microscopes of the twin type set forth is first presented with reference to Figs. 11-14 of' the accompanying drawings, of which Fig.-11 is a front elevation showing diagrammatically a twin microscope of known design,

Fig. "l2 is a plan of the objectunder examination on the microscope,

Fig. 13 is a plan of the standard objeciaon the microscope, l

Fig. 14 is a diagrammatic reproduction of the twin image visible in the eye piece of the microscope.

The microscope shown in Fig. 11 essentially consists of a stand T formed with two arms a, a projecting therefrom, two objectives b, b' of substantially equal focal length, which are mounted on said arms, their axes being parallel to each other; rack and pinion gears c, c for simultaneously focussing both objectives; two stages d, d',

individually adjustable, on which the standard object o and the objeot'o' to be tested are placed; electric lamps e, e' e'nclosed in shades foi illuminating the surfaces of the objects concerned; light reflecting means f, f' enclosed in a casing g; and one single eye piece i mounted in the'middle of vsaid casing with its optical axis substantially in line with the vertical main plane of symmetry `S-S of the whole instrument; the said reflecting means are so arranged and cooperatively associated with both objectives b, b' and the eye piece i, that magnified images O, O' of 'the upper faces of the plates o, o' (Figs. 12-l3) are simultaneously visible in said eye piece in juxtaposition to each other: As seen in Fig. i4 each image O, O' occupies within the field of vision of the eye piece i a semicircular area.

Supposing the surface of plate o has been ground-following roughing on a planing ma.- chine-by a grinding wheel of flne grain, while plate o' has been ground by a grinding wheel of coarser grain: On inspection under the comparison microscope (Fig. 11) plate o will present a magnified image O showing thin shadow lines, closelyassembled and indicating, that the in- -spected surface is in rather smooth-finishedcondition, while image O being a magnication of plate o' and showing broader shadow lines, wider apart from each other, indicates, that the plate o is still in unfinished condition.

As a matter of fact twin microscopes of the 10 design described with reference to Fig. 11 can be used for testing only relatively small objects, commensurate to the size of the stages d, d' and fitting intov the space between stage and objective. y f 15 Moreover because of their specific design, heavy weight and bulkiness the microscopes concerned are unfit for instance for examining large plates, more especially the inner sections thereof,

or for inspecting surfaces generally difficult of zo access, which are located for instance close to recesses, undercut portions, or inl narrow passages, receding cornersetc. as will be elucidated in detail hereinafter with reference to Figs. i and 5.

The exposed and unprotected position of their objectives, stages, lighting devices etc. calls for rather cautious treatment of such microscopes. They are altogether subject to be damaged if roughly handled. No wonder, that they are to be seen only in research laboratories and the like and 'have not found their Way into work shops.

The primary object of this invention is to overcome the aforesaid drawbacks,` inherent to twin microscopes of known design, by so ite-designing the latter, that they can be used to advantage in a great variety of fields, including work shops, and for carrying out testing operations under a great many different conditions as regards shape, size, position and accessibility of the surfaces to be tested: For instance in the grinding shops of motor manufacturing plants, where various close fitting parts, such as the bearings and crank pins of multiple throw crank shafts, while chucked on grinding machines must be inspected, or where the working faces of pistons, valves, cams, gear vwheels etc., made in large quantities'and having Fig. 2 is a verticall section taken on line II-II in Fig. 1,

Fig. 3 B a plan partly in section on line III- III Ain Fig Fig.

4 is a side elevation drawn in a smaller scale of the improved twin-microscope. of which the stand is removed, and which is shown in its application for testing various sections of large surfaces, I I

Fig. 5is a front elevation showing the microscope in its application fosl inspecting the circumferential faces of a crank pin of a crank shaft, Fig. 6 is a section taken vertically online VI -VI of Fig. 8, throughs` structurally modified microscope designed according to this invention,

Fig. '1 is another vertical section taken on line VII-VII in Fig. 8,

Fig. 8 is a plan,

Fig. 9 is a fragmentary section horizontally taken on line IX in Fig. 6 through the lower portion of the microscope. l

Fig. 10 is.a fragmentary section taken vertically through a microscope ofthe general type shown in but of modified design as far as the primary objective and accessoriai parts are concerned:

Figs. 11-14 relating to the prior art have been referred to in detail vhereinbefore; (as to the inclusion of the prior artin U. B.- patent specications for elucidating an invention see U. S. Patent 20,314 to Adams of May 25, 1858 and U. 8. Patent 1,970,236 to Kluge et al. (August 14, 1934) Sheet 1 of the drawings, and pages 1-3 of the specification). ,l

Whereas with known microscopes of the type shown in Fig. 11, the objectives b, b' are both in staggered but strictly symmetrical disposition relatively to the eye piece i and to the stand T, the eye piece and objectives of the twin-microscopes re-designed4 according to this invention are differently arranged:

As seen in Figs. 1, 4 and 10 one of the objectives, hereinafter called the primary one, which is to produce enlarged image of the illuminated surface of the object to be tested, is arranged directly underneath'the eye piece, so that the optical axis of the latter is in line Awith or coaxial to the bundle of light rays upwardly proceeding from said primary objectives-while the other objectives-hereinafter called the secondary ones-which are associated with the standard object, are arranged in staggered position with re-l spect to the said eye piece. A

Referring no'w more in detail to the microscope shown by way of an example in Figs. 1-5, the.

- 9,040,006 structed passages, forinstance into motorcylin- :estive ituairecauainsttnsmasrdobieet I (Fig. 1),! (Fig.4) andisarrangedinstaggered position to the eye piece 2l.; rack and pinion gears Il, I1 are provided within said casing for individually focussing said objectives, and prisms Il, Il or kindred reflecting means for re-directing the bundle 'of light rays issuing from the secondary objective I4 into the eye piece 2l; electric lamps 21, Il attached to said casing I2 and enclosed in a protecting cover or hood 28 for illuminating the objects concerned. as indicated by dot and dash lines in Figs. 2. 4 and 5; a stand 2| detachably secured to said support I8 by means of a stay-bolt 22, tightly fitting into a corresponding 1 hole of the support, and a clamping screw 28; a stage 24, adjustably fixed by means of a rack andpinion gear to said stand, for holding the object to be tested; and another stage 24, ladjustably fixed by means of a rack and pinion gear to the support I0, for accommodating the standard object. An accessorial structural feature of importance of the support Iii and its casing I2 consists therein, that they are step-shaped at their base so as 'to present broken faces-best seen in Fig.4thus being adapted to be placed directly upon any section of a flat object to be tested; and that apertures a, a' are provided for admitting light illuminating the objects under examination.'

and light reflected therefrom into the objectives I4, I8; it should be further noted, that the casing II-being broader than the diameter of the objectives and laterally offsetting from the latter at the apertures a. apresents shelters, within which theobjectives I4, I5 are safely enclosed and well protected against damages.

In order to facilitate the handling of the microscope on being placed upon rounded objects, such as crank pins of a crank shaft (Fig. 5), rollers 32, 34 or the like may be conveniently provided at the support I li, journalled within arms, which are pivotally fixed at I3, l5 within recesses provided taie the base of casing I2, so as to be capable of ing swung around their pivots into an outward operative position (Fig. 5) and of being returned into their idle position shown in Figs. 1 and 2.

A 4structurally modified type of twin-microscopes, designed according to this invention and being shown'in Figs. 6,-9, is adapted for inspecting the concave inner working faces of hollow or cupshaped pieces 4of work such as motor cylinders, bearings, ball races etc.

The support of the microscope tubular shell 40 of preferably cylindrical shape, being closed at the top by a lid 4I, which carries eye piece and being provided4 at itsV lower end with an aperture 42 and a frame 43; within the latter the objectives are adjustably mounted; the

primary objective 44, facing said aperture 42 is arranged at right angles to the optical axis of the eyepiece 50 and is-cooperatively associated with a primary reiector 48 arranged truly underneath,

the eye-piece for .re-directing thereinto the image of the object C' to be tested-for instance the ground inner walls of a motor cylinder-while the image of the standard object C, refracted by the secondary objective 46 is reected twice by a secondary reflector 49 having two reflecting consists of a` faces, which is arranged closely underneath the l eyepiece 58 in staggered position thereto.

A stage 51|:y for accommodating the standard object C is adjustably connected to the frame 43 by means of aA clamping screw having a knurled head and extending through a slt of stage 54 indicated by dash lines. Screw 23 is accessible through an aperture provided in the lower end oi shell 40.

Means are'provided for individually focussing the said objectives, which comprise a. rack and pinion gear 45 (Fig. 9) attached to the primary objective 44 and la screw and nut gear 41, attached to the secondary objective 46; both gears 45, 41 are operable above the microscope being tted with rotary connecting rods 55, 51, journalled in lid 4I and having knurld heads.

Lighting devices-preferably electriclamps 61, BB-are arranged within the shell 40 at a suitable distance above the said aperture v42 and stage 54 respectively. for illuminating the surfaces of the.

objects C, C' to be examined and compared with each other. i Handling, supporting and guiding means are provided at the shell 40 of the microscope for facilitating the manipulation of the latter on being inserted into the object to be tested.

In the embodiment of the invention shown in Figs. 6-8 by way of an example said supporting and handling means comprise a split ange 10 studded with handles 1|, 12, which frictionally engages the shell 40 and i's adjustably fixed thereon by means of'a clamping screw 13 and a key 14 projecting from the shell 40; the said guiding means comprise a pair of distance rings 80, 8|, which frictionally engage the shell 40 in excentric position thereto and are adjustably fitted thereon'by suitable clamping means (not Y shown) It will be noted, that the modified arrangement, namely indirect cooperation of the primary objective 44 with the eyepiece 50 through a reflector 48, shown and described with reference to Figs. 6 9, is due to the excentric displacement of the surface C' to be inspected relatively to the axis of the eyepiece.

vIt will also be understood, that various other changes and modications as regards the structural details o! comparison microscopes oi the improved design described above may beconven` iently made, without departing irom the salient ideas oi' this invention, and without sacrificing and advantages attained thereby:

For instance the primary objective and its reflector 48 (Fig. 6), provided for re-directing the image oi.' the object C' to be tested into the eyepiece 40, may be diierently arranged.

As shown in Fig. 10 the;primary objective 84 may be placed with its optical axis in line with that of the eyepiece 90, truly underneath the latter, whilethe reflector 8l is arranged below said objective i'or cooperation therewith in the manner indicated by dot and dash lines in Fig. 10.

1. In a comparison microscope the combination with a support having -a step shaped base, of

two objectives spaced from each other, a primary and a secondary one, which are adjustably mounted in said support with theircentral axes being parallel to each other, an eye piece mounted on said support coaxially to the bundle oi light rays issuing from said primary objective, reflecting elements arranged underneath said eyeipiece in staggered position thereto, so as to redirect into said eye piece the bundle of light rays r 2. In a comparison microscopethe combina-y" tion with a support having a Step shapedbase, of

two objectives spaced from each other, a primary anda secondary one, which are adjustably mounted in said'support with ltheir'centralaxes being parallel to each other. an eye piece mounted on said support coaxially tothe bundle of" light rays issuingfirom said primary objective, reilecting elements arranged underneath said eye piece in staggered position thereto, so. as to-redirect into said eye piece the bundle of lightl rays issuing from said secondary objective.` and a stage adjustably attached to-said support for cooperation with the secondary objective,4 the latter be- 'ing arranged at a higher level than lthe primary "mounted in said support with their -central axes being parallel to each other, an eye piece mount-v ed on said support coaxially to the bundle of light rays issuing from said primary objective, reecting elements arranged underneath said eye piece in staggered position thereto, so as to re-direct into said eye piece the bundle of light rays issuing from said secondary objectivefand a stage adjustably attached to said support for cooperation with the secondary objective, the latter being arranged at a higher level than the primary one, recesses being formed at the bottom of said step shaped base and rollers being pivotally xed therein for` supporting the microscope.' 4. In a comparison microscope the combina-- tion with a support having a step shaped base, of two objectives spaced from each other, a primary and a secondary one, which are adjustably mounted in said support with their central axes being parallel to each other, an eye piece mounted on said support coaxially to the bundle of light rays issuing from'said primary objective, reiiecting elements arranged underneath said eye piece in staggered position thereto, so as to re-direct into said eye piece the bundlel o! light rays issuing from said secondary objective, and a stage adjustably attacheco said support for cooperation with the secondary objective, the latter being arranged at a higher level than the primary one, the support being detachably ilxed on a stand, the latter having a stage adjustably attached for cooperation with the primary objective. v

5. In a comparison microscope the combination with a support having a step shaped base, of two objectives spaced from each other, a primary and a secondary one, which are adjustably mounted in said support with their central axes being parallel to each other, an eye piece. mounted on said support coaxially to the bundle of light rays issuing fromsaid primary objective, reecting elements arranged underneath said eye piece in staggered position thereto, so as to re-direcj'I into said eye piece the bundle of light rays issuing from said secondary objective, and a stage adjustably attached to said support for cooperation with the secondary objective, the latter being arranged at a higher level than the primary one, the support being formed with a casing enclosing said objectives. and apertures being provided at the base of said casing for the admission of light to the `objects under examination and to said objectives.

6. In a comparison rr toscope the combination with a support ha' -ng a step shaped base. of two objectives spaced from each other, va

primary and a secondary one, which are adjustably mounted in said support with their central axes bei-ng parallel to each other, an eye piece mounted on said support=coaxia1ly to the bundle or light rays issuing from said primary objective, reiiecting elements arranged underneath said eye piece in staggered position thereto, so as to redirect into said eye piece the bundle of light rays issuing from said secondary objective, and a stage adJustably attached to said support for coopera-- a secondary one, which are adjustably mounted in said support/with their'central axes -being to eachother. an eye piece mounted-on said support coaxially to the bundle oi light raysissuing from said primary objective,

elements arranged underneath said eye piece in' staggered position theretosc as to re-direct into said eye piece the bundlev 'of light rays issuing from said secondary' obiective. and a stage ad- 'Justably attached to said support for cooperation with the secondary objective, the latter being arranged at a higher level than the primary one; the support being formed with a casing enclosingv said objectives, apertures being provided at the base of said casing for the admission of light to the objects under examination and to said objectives.- sources of light being fitted to said casing.

and means provided for protecting the said sources of light.

O'I'I'O URSINUB. 

